A new continuum damage mechanics–based two-scale model for high-cycle fatigue life prediction considering the two-segment characteristic in S-N curves

In this study, we propose a new two-scale fatigue model based on continuum damage mechanics. A representative volume element (RVE) consisting of microinclusions and a matrix is constructed. Further, damage-coupled constitutive equations are derived. The degradation in the mechanical properties of the RVE is determined by the damaged inclusions and matrix using the Mori-Tanaka scheme. A numerical calculation of the fatigue lives of notched specimens is executed. This new model predicts high-cycle fatigue (HCF) life more effectively, considering the two-segment characteristic of S-N curves of smooth specimens. This study provides novel insights into the evolution mechanism of HCF damage.